Cooler temperatures and rainfall in recent months may have made the arachnids more likely to be on the move, said Texas Parks and Wildlife biologist Ross Winton. Male tarantulas tend to be more active than females, he said.

Tarantulas usually live in hollowed-out logs, or in burrows in open fields, said Austin Nature and Science Center exhibit specialist Haley Rayo. Floodwaters could force tarantulas out of their burrows, leading to more encounters.

Tarantulas bite and have hairs on their abdomen that may cause itching and irritation, but they don't pose a significant threat to humans, Winton said.